Photochromic lenses that turn dark when exposed to the ultraviolet rays of the sun.

Trifocal Lens

See Lens, Trifocal.


Lens that offers similar lightweight and impact resistant characteristics like polycarbonate but offers better clarity then poly due to higher Abbe value.

Ultraviolet Coating (UV)

A coating that blocks ultraviolet rays.

Utilization Review

The process of reviewing the appropriateness and quality of care provided to patients.

Value-adding Process

Those activities that transform an input into a customer-usable output.

VDT (Video Display Terminal)

A term that refers to a specific type of glasses designed to be worn while working on the computer to address the different visual requirements and distance of the wearer. May also be referred to as occupational glasses and addresses a condition commonly referred to as computer vision syndrome. Usually VDT glasses are only covered as a second pair if they are ordered at the same time as the primary or main pair.

Visual Acuity

Degree of visual sharpness, as determined by a conformance to or deviation from the standard 20/20 measurement.